NaCryolite
Sodium hexafluoroaluminate · Sodium aluminum fluoride · Na₃AlF₆
| Molecular formula | Na₃AlF₆ |
|---|---|
| CAS No. | 13775-53-6 |
| Appearance | White or light pink crystalline powder, sand or granules; odorless |
| Grade | Industrial grade |
| Specific gravity | 2.95–3.05 g/cm³ |
| Melting point | About 1000 ℃ |
| Specific heat | 1.056 J/g·℃ (18–100 ℃) |
| Solubility | Slightly soluble in water; insoluble in anhydrous hydrogen fluoride; absorbs moisture easily |
| Standard | GB/T 4291-2017 |
| Packing | N.W. 25 kg plastic woven bag with liner, or as per customer’s requirement |
Types by form and molecular ratio
Cryolite is divided into high and low molecular ratio grades according to the molecular ratio of sodium fluoride to aluminum fluoride.
- Low melting point and fast melting speed, shortening the time to reach normal working state
- Molecular ratio adjustable over a wide range, suiting different periods of the electrolytic cell
- Low moisture content and small fluorine loss
- Low production cost, raw materials easy to obtain
- Molecular ratio from 1.75 to 2.5
- Adjustable molecular ratio
- Good fluidity, suitable for mechanized blanking
- High actual yield in electrolytic production, reducing the cost of electrolytic aluminum
- Molecular ratio 2.5–3.0, especially suitable for electrolytic aluminum production
Specification (GB/T 4291-2017)
| High-molecular ratio grade | F ≥ 52% |
|---|---|
| Common grade | F ≥ 53% |
Applications
- Aluminum electrolysis flux: in the Hall–Héroult method, a cryolite-based fluoride melt is the solvent for producing metallic aluminum, and no compound has yet been found to replace it. It is stable, does not decompose, volatilize or deliquesce under normal conditions, has a melting point higher than aluminum, and offers good electrical conductivity and energy saving.
- Abrasives: wear-resistant additive for grinding wheels, abrasive discs and abrasive belts, improving wear resistance and cutting/grinding performance while extending service life and shelf life.
- Glass: production of opal (milky white) glass.
- Metallurgy: electrolyte component in the production of aluminum alloys, ferroalloys and “boiling” steel.